“For many years naval planners have worked on the development of a seaplane concept. We have been able to build the submarines to replenish and support her—the tenders and floating docks and mobile logistics to exploit her fully. Now it looks as if our dream has come true with the new P6M SeaMaster. She has speed; she has range. She has rough water capabilities. She is capable of delivering atomic bombs and mines against enemy targets.”
These are the words of Admiral Arleigh Burke, Chief of Naval Operations, speaking at Philadelphia on November 1, 1955.
Since that time this high-speed, sweptwing, jet-powered seaplane has shown not only that she is the solution to the problem of finding a seaplane suitable for the operations made possible by existing support equipment, but that she has actually swung the pendulum the other way. Now the challenge is to develop support equipment and procedures capable of utilizing the full versatility offered by the SeaMaster.
The Navy, with the close cooperation of the Martin Company—designer and builder of this first jet seaplane—is developing competent handling apparatus and techniques to be ready for the P6M by the time she is in production.
The ultimate hope of those directly concerned with developing the waterbased aircraft concept is to provide a program comprised of three distinct types of bases: forward area, intermediate, and rear area permanent bases similar to those now existing.
Forward area operations could employ a task force of a predetermined number of aircraft and enough submarines with organic equipment to support them. This force could move into the enemy’s backyard, operate quickly and effectively, and depart silently—leaving behind only the empty sea. Moving from place to place, this force would leave no sign of where it had been, nor any indication of where it was going. During these activities the seaplanes would be refueled, supplied with spares as needed, and have required maintenance performed; the crews would receive hot food, have access to showers and clean clothing, and perhaps be rotated with spare crews on the submarines.
Former Assistant Secretary of the Navy James H. Smith, Jr., mentioned the possibility of this type of seaplane deployment in the February, 1955, issue of the U. S. Naval Institute Proceedings under his discussion of “Mobile Sea Bases in Nuclear Warfare.” But these operations are now far beyond the discussion stage. Already being built for the SeaMaster are a beaching vehicle that permits the seaplane to taxi onto a ramp under its own power, a floating dock enabling maintenance crews to accomplish repair work, and other support equipment making possible an efficient waterbasing operation.
As for the details of such action, much has been done to increase the ability of a submarine to support aircraft during extended activity. In an exercise during the period from May 7 to May 11, 1956, a submarine provided full support for four seaplanes off the Florida Keys. The purpose of this exercise was threefold: to evaluate the capability of a submarine to support seaplanes for several days; to determine what changes would be necessary to accommodate the P6M; and to test the use of a series of inflated rubber cells as a bridge between the submarine and the plane being serviced. The rubber cells, identified as Seald Bins by their manufacturers, The U. S. Rubber Company, were carried on the deck of the submarine.
Actively participating were four P5M aircraft from Patrol Squadron 44, based in Norfolk, Virginia, and the USS Guavina, based in Key West, Florida. Observers included representatives of several interested bureaus and manufacturers, some on the submarine, others aboard the seaplane.
Leaving Key West at 0800 on May 7, the USS Guavina headed for the Dry Tortugas, a group of small islands sixty miles west. When she arrived there her crew anchored the bins and laid a seadrome—four mooring buoys and two sea lane markers. The four aircraft assigned to the operation rendezvoused with the submarine at 1645, landed, and tied up to the buoys. One P5M then approached the Seald Bins, which were some twenty feet from the Guavina. The aircraft’s crew picked up a line streamed aft from the bins, pulled alongside, and moored to them. The bins were then pulled to the Guavina, where the observers stepped onto them and passed easily between the aircraft and the submarine. Spares were transferred and the airplane cast off. Thus was the exercise successfully launched.
For the next four days activities followed this same pattern. The seaplanes tied up to the submarine, refueled, took on token spares, transferred passengers, and cast off. The seadrome site was moved, with the submarine and the P5M’s rendezvousing at Tampa Bay. Sometimes the aircraft stayed overnight at the waterbase site; sometimes they returned to their home base. But always the over-all purpose was the same—to develop new and better techniques of conducting operations between the seaplanes and the submarine. From the very first the P5M’s had no difficulty coming alongside the bins, but there was some confusion in mooring to them. Like other problems in procedure, though, this was soon corrected. Later modifications of the original routine found the bins held fast to the submarine, with a towline trailed. The aircraft picked up the towline and were winched to the floating platform.
By the final day of the exercise the unit was working so smoothly that a P5M could tie up to the Guavina, have stands rigged on one engine for simulated maintenance, take aboard spares, hot food, and gasoline, and cast off—all in less than 45 minutes.
The observers met at the close of the last day, and all agreed the exercise had demonstrated that a submarine could successfully support a number of aircraft in an isolated area, furnishing fuel, spares, hot food, and miscellaneous services on request. The Guavina-type can furnish adequate berths and crew comforts for as many as twenty aircraft crew members.
The observers decided that a soft floating platform between the submarine and the aircraft had been advantageous in refueling and in transferring spares and personnel, but a small boat should be carried aboard the submarine to facilitate the transfer of personnel and small supplies without having the aircraft tie up to the submarine each time.
It was further agreed among the observers that submarine personnel should be familiarized with aircraft equipment and procedures to prevent recurrence of incidents such as the one experienced during the exercise when one man used the ripcord as a handle while passing a parachute from the submarine to the aircraft. They also saw the need for an air liaison officer on the submarine during such operations.
During the exercise it became evident that existing crew-comfort and food-handling arrangements were inadequate. Suggestions for remedying this included developing a portable kit, containing wash basin, toothpaste, shaving equipment, air mattresses, and similar items, to be made available from the submarine. It also was shown that storage facilities—on both the submarine and the aircraft—were not adequate.
The observers concluded that although the aircraft in this exercise did not remain with the submarine throughout the week, their departures were merely a matter of convenience and crew comfort. At no time did they draw supplies and equipment not available at the Guavina. The observers felt that further training exercises, using aircraft from other patrol squadrons, and the Guavina or similar type submarine, should be conducted to improve techniques and to test new methods and ideas intended for use with the SeaMaster.
As a result of the recommendations of the observers during that first exercise, and of later conferences, a second mobile-base operation was scheduled. Conducted from July 16 to July 20, 1956, it again employed the USS Guavina. But this time the aircraft were from Patrol Squadron 56; all crews were completely new to the type of activity planned.
The purpose of this second exercise was—in addition to improving the devices and methods discussed after the first exercise—to test the practicability of transferring personnel and supplies directly from the submarine fueling deck to the aircraft without using a floating platform. It was also hoped to demonstrate the mobile aspects of water-based support and to train VP 56 in water-based techniques. For this exercise the Guavina was rigged with a double layer of tires—gathered from an automobile salvage yard—around the starboard side of the fueling deck and halfway around the stern. These were considered a satisfactory bumper.
The Guavina and the aircraft from VP 56 rendezvoused in the operating area on July 16 and began operations immediately. The first aircraft to arrive landed, taxied to the nylon towline streamed aft of the Guavina, secured it to the port bollard, then cut its engines. As soon as the P5M was under tow the Guavina ballasted the refueling deck down to about two feet of freeboard, and a rubber boat carried steadying lines to the tip floats of the P5M. These lines were secured, and the submarine brought the plane alongside by winching in the towline. Fuel, hot food, and actual spare parts were transferred to the aircraft, which then cast off all lines as the submarine eased forward. When the P5M was clear it started the engines and moved away to allow the second seaplane to come alongside.
The second aircraft was brought alongside with equal ease, but with one variation. The steadying lines
were passed to it by a linethrowing gun, and were secured to the towing pad eyes rather than to the floats.
The steadying lines were thrown to the third aircraft by heaving lines—a means that proved more effective, faster, and safer than either the rubber boat or the linethrowing gun.
After all three aircraft had cast off, one proceeded to Jacksonville, one went to the ramp at Key West, and the third landed at the buoy at Key West. The Guavina, meanwhile, headed for the Dry Tortugas Islands, where the P5M’s joined her the following morning.
Activities during the remainder of the week followed a similar pattern. Tie-up operations and refueling were conducted daily, with the seaplanes deploying to separate bases each night and rendezvousing with the USS Guavina at a new location the next morning. The exercise shifted from Key West to the Dry Tortugas, from there to Tampa Bay, then on to Panama City, and finally back to Tampa Bay.
Over-all time and technique improved constantly. It was found that using the bow pendant as a bow line leading forward on the submarine, and leading the towline aft, almost completely damped the motion between the aircraft and the submarine.
The high spot of the entire week was a time trial on the final day of the exercise. Starting from a submerged position, the USS Guavina surfaced, rigged, replenished three aircraft alongside—allowing each at least five minutes with the refueling hose attached and resubmerged.
This very successful exercise proved conclusively that P5M’s could tie up directly alongside the supporting submarine, eliminating the need for floating platforms in forward water bases. It was demonstrated again that a submarine can replenish a number of aircraft in isolated areas—and do it rapidly. The limiting factor in this type of operation proved to be the effect of adverse sea conditions on the ability of the aircraft to take off—not on the ability of the submarine to give support, as was initially feared. No special training is required for pilots participating in waterbased operations, but the submariners must learn to be constantly aware of wind direction. Mobility was proved especially in this second exercise, which covered almost the entire Florida west coast during the five days of activity.
Foremost among problems yet to be overcome is that of making the aircraft more habitable, and action is being taken to accomplish this. Suggestions include: a 15- gallon fresh-water tank and a basin for personal sanitation; a refrigerator for storing perishable foods between refills; and a portable electric generator to replace the present auxiliary power unit.
More exercises of this type would familiarize additional squadrons with this refueling technique, and would undoubtedly develop further refinements to existing procedures. But those who participated in the exercises feel that fleet submarines could support the Martin P6M SeaMaster today!
A graduate of the U. S. Naval Academy in the Class of 1946, Lieutenant Dakos served on the Boxer, Belleau Wood, Goodrich, and Carry. He also served on the staffs of Commander, Amphibious Group 2 and Commander, Carrier Division 5. As an engineer in the Product Utilization Section of the Martin Company, he was present throughout both exercises described in this article. Mr. Dakos is now with the Koppers Company as a sales engineer.